To examine the association between breastfeeding pattern and likelihood of myopia in 6-7y children, a retrospective case-control study is designed in National Nutrition and Food Technology research Institute of Iran. This study will try to assess almost all cofactors which may relate to myopia; such as child's age, sex, height, birth weight, maternal age at delivery, IQ (intelligence quotient), near work, parental education and ethnicity, parental myopia, child n-3(omega-3) fatty acid and refined carbohydrate intake, maternal n-3 fatty acid intake, n-3 fatty acid intake while infancy, physical activity and other confounding factors which may have an effect on the relationship among breastfeeding pattern and myopia.